Floater based flow control device for gravity iv sets

ABSTRACT

A flow control device includes an upper housing, a lower housing, a chamber interposed between and defined by the upper and lower housings, and a valve member. The upper housing includes a primary inlet having an internal surface defining a cavity and a secondary inlet. The lower housing defines an outlet of the flow control device. The chamber fluidly connects the primary and secondary inlets with the outlet. A valve member is reciprocally disposed at least partially in the cavity and partially in the chamber to (i) selectively permit fluid flow in the primary inlet in a first direction when a fluid level in the chamber is below a predetermined level, and (ii) prevent fluid backflow in a second direction opposite to the first direction when the fluid level in the chamber is above the predetermined level.

TECHNICAL FIELD

The present disclosure generally relates to flow control devices, andmore particularly to flow control devices having a valve member capableof preventing under-infusion in IV sets with a secondary line, as wellas preventing backflow of drug from the secondary line into the primaryline.

BACKGROUND

Infusion IV sets are generally used in infusion therapy in order todeliver medication from a pre-filled container, e.g., an IV bottle orbag containing the desired medication, to a patient. Generally, the IVtubing is connected to a catheter and inserted into the localized areato be treated. In some cases, there is a need to deliver multiplemedications to the patient in potentially differing dosages, therebycausing the need for an IV extension set having multiple branches oftubings or fluid lines through which the multiple medications may bedispensed to the patient.

Patients are commonly injected with IV solutions that are initiallyprovided in the IV bottle or bag and dripped into the vein of thepatient through an IV line. A flow control device, for example, a checkvalve, is also commonly included in the IV line to permit fluid flowonly in the direction of the patient. This ensures that the medicationflows downstream toward the patient, not upstream toward the IV bottleor bag.

During infusion with IV sets, a secondary drug feed could potentiallyflow backwards into primary IV line leading to under infusion of thesecondary drug. Though a check valve may be positioned in the primaryline to prevent backflow, check valves may fail. A common reason forcheck valve failure is due to debris existing in infusates.Additionally, under-infusion frequently occurs due to air entering thesecondary line thereby causing some of the secondary drug to remain inthe secondary line (undelivered medication). Air entering the IV linemay have undesirable effects such as causing air embolisms for thepatient.

The description provided in the background section should not be assumedto be prior art merely because it is mentioned in or associated with thebackground section. The background section may include information thatdescribes one or more aspects of the subject technology.

SUMMARY

In accordance with some embodiments of the present disclosure, a flowcontrol device may include an upper housing including a primary inlethaving an internal surface defining a cavity and a secondary inlet, alower housing defining an outlet of the flow control device, and achamber interposed between and defined by the upper and lower housingsfor fluidly connecting the primary and secondary inlets with the outlet.The valve member may be reciprocally disposed at least partially in thecavity and partially in the chamber to (i) selectively permit fluid flowin the primary inlet in a first direction when a fluid level in thechamber is below a predetermined level, and (ii) prevent fluid backflowin a second direction opposite to the first direction when the fluidlevel in the chamber is above the predetermined level.

In accordance with some embodiments, an intravenous (IV) set may includea primary IV line and a secondary IV line, and a flow control device.The flow control device may include an upper housing, a lower housingcoupled to the upper housing, and a chamber defined between the upperand lower housings. The upper housing may include a primary inletfluidly communicating the primary IV line with the chamber, and asecondary inlet fluidly communicating the secondary IV line with thechamber. The flow control device may further include a valve memberhaving a base disposed in the chamber and a plurality of legs extendinglongitudinally from the base into the primary inlet, the floating valvemember being displaceable in a proximal direction by a buoyant forceexerted on the base when a level of fluid in the chamber exceeds apredetermined level.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the subject technology asclaimed. It is also to be understood that other aspects may be utilized,and changes may be made without departing from the scope of the subjecttechnology.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of theembodiments, and should not be viewed as exclusive embodiments. Thesubject matter disclosed is capable of considerable modifications,alterations, combinations, and equivalents in form and function, as willoccur to those skilled in the art and having the benefit of thisdisclosure.

FIG. 1 illustrates a multiple line IV extension set that includes a flowcontrol device, in accordance with some embodiments of the presentdisclosure.

FIG. 2A illustrates a cross-sectional view of a flow control device, inaccordance with some embodiments of the present disclosure.

FIG. 2B illustrates an enlarged partial cross-sectional view of the flowcontrol device and valve member of FIG. 2A, in accordance with someembodiments of the present disclosure.

FIG. 2C illustrates a perspective view of an upper housing of the flowcontrol device of FIG. 2A in accordance with some embodiments.

FIG. 2D illustrates a cross-sectional view of the upper housing of theflow control device of FIG. 2A in accordance with some embodiments.

FIG. 3 illustrates a perspective view of a valve member of a flowcontrol device, in accordance with some embodiments of the presentdisclosure.

FIG. 4 illustrates a perspective view of a valve member and sealingmember of a flow control device, in accordance with some embodiments ofthe present disclosure.

FIG. 5 is a cross-sectional view of a flow control device in an openstate when subjected to an upstream force, where the drug level in thechamber is below a predetermined level, in accordance with someembodiments of the present disclosure.

FIG. 6 is a cross-sectional view of the flow control device of FIG. 5 ina closed state, where the drug level is above a predetermined amount andapplies a buoyant force to the valve member, in accordance with someembodiments of the present disclosure.

FIG. 7 is a cross-sectional view of the flow control device of FIG. 5 ina closed state, where fluid flows from the secondary inlet into thechamber in accordance with some embodiments of the present disclosure.

FIG. 8 is a cross-sectional view of the flow control device of FIG. 5 inan open state, where fluid flow from the secondary inlet into thechamber is complete, and the drug level in the chamber has fallen belowa predetermined level, in accordance with some embodiments of thepresent disclosure.

FIG. 9 illustrates a cross-sectional view of a flow control devicehaving a valve member, in accordance with some embodiments of thepresent disclosure.

FIG. 10 illustrates a cross-sectional view of a flow control devicehaving a valve member, in accordance with some embodiments of thepresent disclosure.

FIG. 11 illustrates a perspective view of the valve member of FIG. 10,in accordance with some embodiments of the present disclosure.

FIG. 12 illustrates a cross-sectional view of a flow control devicehaving a valve member, in accordance with some embodiments of thepresent disclosure.

FIG. 13 illustrates a perspective view of the valve member of FIG. 12,in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below describes variousconfigurations of the subject technology and is not intended torepresent the only configurations in which the subject technology may bepracticed. The detailed description includes specific details for thepurpose of providing a thorough understanding of the subject technology.Accordingly, dimensions may be provided in regard to certain aspects asnon-limiting examples. However, it will be apparent to those skilled inthe art that the subject technology may be practiced without thesespecific details. In some instances, well-known structures andcomponents are shown in block diagram form in order to avoid obscuringthe concepts of the subject technology.

It is to be understood that the present disclosure includes examples ofthe subject technology and does not limit the scope of the appendedclaims. Various aspects of the subject technology will now be disclosedaccording to particular but non-limiting examples. Various embodimentsdescribed in the present disclosure may be carried out in different waysand variations, and in accordance with a desired application orimplementation.

The present description relates in general to flow control devices, andmore particularly to flow control devices having a valve member capableof preventing under infusion in IV sets with a secondary line, as wellas preventing backflow of drug from the secondary line into the primaryline.

IV sets with a secondary line tend to experience under-infusion of thesecondary drug due to failure of the check valve in the primary line.The most frequent causes of failure of the check valve are due to debrisaccumulated at the time of spiking and seeping of drug in the secondaryline into the primary line at low pressures. A common cause ofunder-infusion is dilution of drug at the time of back priming of thesecondary IV and also at the time of equal head in the primary andsecondary lines. Other causes include dead volume in the secondary line,as well as time taken to infuse the drug. The flow control devices ofthe various embodiments described herein overcome the above issuescommonly associated with IV sets having primary and secondary lines.

In accordance with various embodiments of the present disclosure, a flowcontrol device may include an upper housing having a primary inlet and asecondary inlet, a lower housing coupled to the upper housing, a chamberdefined between the upper and lower housings, and a floating valvemember disposed at least partially in the chamber and partially in theprimary inlet. In some embodiments, the upper housing may have aninternal surface with a circumferential lip at a distal end thereof. Thecircumferential lip may be oriented projecting radially inwards towardsa central longitudinal axis of the primary inlet.

In some embodiments, the valve member may have a base and a plurality oflegs extending longitudinally from the base into the primary inlet. Thelegs may be spaced apart from each other with adjacent pairs of the legseach defining a flow portion or slot through which fluid entering theprimary inlet flows into the chamber. In some embodiments, each of thelegs may terminate in a flange at a proximal end of the valve member. Inother embodiments, the valve member may be structured as a body with acentral aperture and a plurality of axially extending slots throughwhich fluid flowing into the primary inlet may enter the chamber.

In operation, when the fluid level in the chamber is below apredetermined level, and when the valve member is subject to a netupstream force (i.e., a force applied by a fluid flowing from theprimary inlet towards the chamber that exceeds that of any buoyant forceapplied by fluid in the chamber), the valve member may be translateddistally (downstream) to a position where each flange is seated on thecircumferential lip. Accordingly, the valve member may be placed in anopen state whereby fluid from the primary IV line may enter the chambervia the primary inlet.

In accordance with some embodiments, the valve member may include asealing member coupled to at least a portion of an upper surface of thebase.

In operation, when the fluid level in the chamber is above apredetermined level and when the valve member is subject to a netdownstream force (i.e., a buoyant force applied by a fluid in thechamber that exceeds any upstream force applied by a fluid flowing fromthe primary inlet towards the chamber), the valve member may betranslated proximally (upstream) to a position where the sealing membercontacts and seals against the internal surface of the upper housing.Accordingly, fluid flow from the chamber into the primary inlet isblocked, thereby preventing fluid backflow into the primary inlet. Assuch, under-infusion of the secondary drug, which commonly occurs as aresult of the secondary drug flowing back into the primary inlet fromthe chamber, is prevented. Preventing backflow of the fluid isadvantageous in that it restricts undesirable particulate matter, forexample, contained in the secondary drug from flowing back through thevalve member and preventing the patient from receiving the proper drugdosage concentration or from timely delivery of the drug.

FIG. 1 illustrates a multiple line IV extension set 1 that includes aflow control device 100, 200, 300, in accordance with some embodimentsof the present disclosure. IV set 1 includes a primary fluid system 15and a secondary fluid system 25. An IV pump (not shown) receives fluidfrom primary fluid system 15 and secondary fluid system 25 via a primaryIV line 5 and may control and dispense the fluids therefrom to a patient50.

In some embodiments, primary fluid system 15 may include a primary fluidsource such as a primary fluid bag 10 which may include or containsaline solution or other medicinal fluid or drug to be administered tothe patient 50. As illustrated, primary IV line 5 carries primary fluidfrom a drip chamber 12 to flow control device 100, 200, 300. As shall bedescribed further with respect to the following figures, flow controldevice 100, 200, 300 may be disposed in primary IV line 5 and allowfluid flow from primary fluid bag 10 to the IV pump (not illustrated)while preventing reverse flow (backflow) of fluid from secondary fluidsystem 25 toward primary fluid bag 10. In accordance with someembodiments, secondary fluid system 25 includes secondary fluid sourcesuch as a secondary fluid bag 8, which may contain drugs or othersecondary fluid to be supplied to the patient 50 for treatment. Asdepicted, the IV set 1 may further include a secondary IV line 7 whichcarries flow from drip chamber 22 to the flow control device 100, 200,300.

FIG. 2A illustrates a cross-sectional view of a flow control device 100,in accordance with some embodiments of the present disclosure. FIG. 2Billustrates an enlarged partial cross-sectional view of the flow controldevice 100 and valve member of FIG. 2A, in accordance with someembodiments of the present disclosure. As depicted, the flow controldevice 100 may include an upper housing 120, a lower housing 140 coupledto the upper housing 120, a chamber 150 defined between the upperhousing 120 and the lower housing 140, and a floating valve member 110disposed at least partially in the chamber. The upper housing may alsoinclude a secondary inlet 130 for fluidly communicating the secondary IVline 7 with the chamber 150. Referring to FIG. 2A, the flow controldevice is displayed in cross-sectional view to more clearly illustratesome of the features of the valve member 100. As depicted, the flowcontrol device 100 may be in the form of an axially extending bodydefining a central longitudinal axis X. The body may be generallycylindrical (or tubular) or may have any other shape with a hollowinterior capable of defining a chamber.

FIG. 2C illustrates a perspective view of an upper housing of the flowcontrol device of FIG. 2A in accordance with some embodiments. FIG. 2Dillustrates a cross-sectional view of the upper housing of the flowcontrol device of FIG. 2A in accordance with some embodiments. Referringto FIGS. 2C and 2D, the upper housing 120 may include a primary inlet125 for fluidly communicating the primary IV line 5 with the chamber150. As depicted, the primary inlet 125 may have an internal surface127, which defines a cavity 135 in which at least a portion of the valvemember 100 is disposed. The cavity 135 may form a part of the primaryinlet 125, or may be otherwise fluidly communicated with the primaryinlet 125. Accordingly, fluid flowing from the primary inlet 125 to thechannel 150 may flow via the cavity 125. In some embodiments, theinternal surface 127 defining the cavity may have a circumferential lip175 at a distal end thereof. As depicted, the circumferential lip 175may be oriented projecting radially inwards towards a centrallongitudinal axis Xi (illustrated in FIG. 2A) of the primary inlet 125.

Referring back to FIG. 2A, in some embodiments of the present disclosurethe lower housing 140 may be coupled distally to the upper housing 120,and may further define an outlet 145 through which medication or drugsfrom the primary and secondary inlets may be delivered to the patient50. As illustrated, a radial extent of the lower housing 140 at aproximal end thereof (the end directly coupled to the upper housing 120)may be greater than the radial extent at a distal end. However, thevarious embodiments of the present disclosure are not specificallylimited to the aforementioned configuration and a shape andconfiguration of the lower housing 140 may vary for the intendedpurposes while still embodying the working principles described herein.The lower housing 140 and the upper housing 120 may axially contact eachother to co-operatively form the chamber 150 of the flow control device100. In the depicted embodiments, the floating valve member 110 may bemounted partially in the cavity 135 and partially in the chamber 150.The floating valve member 110 may selectively permit fluid flow from theprimary IV line 5, through the primary inlet 120, and into the chamber150 when a fluid level in the chamber 150 falls below a predeterminedlevel Further, the valve member 110 may operate to prevent fluidbackflow into the primary inlet 120 from the secondary inlet 130 and thechamber 150 when the fluid level in the chamber 150 is above thepredetermined level and exerts a buoyant force on the valve member 110.

FIG. 3 illustrates a perspective view of a valve member 110 of a flowcontrol device, in accordance with some embodiments of the presentdisclosure. According to various aspects of the present disclosure, thevalve member 110 may include a base 165 and a main body 160 extendingproximally from the base 165. In some embodiments, the base 165 may bein the form of a disc or any other circular or semi-circular platehaving an upper surface 167 and a lower surface 169. The size or surfacearea of the base 165 may be selected specifically to allow for maximumexposure to the fluid in the chamber 150 so as to overcome fluid forceof the fluid entering the primary inlet 125 from the primary IV tubing5. For example, the greater the size of the base 165, the greater thesurface area acted upon by the fluid in the chamber. Accordingly, thevalve member 110 may be designed so as open and close the primary inletbased on a specific threshold force.

As depicted, the main body 160 may have a plurality of legs 161extending longitudinally from the base 165 into the cavity 135 of theprimary inlet 125. The legs 161 may each extend longitudinally from anupper surface 167 of the base 165. In some embodiments, the legs 161 maybe oriented substantially perpendicularly with respect to the uppersurface 167 of the base 165. In particular, the legs 161 may extend andprotrude substantially perpendicularly at a height above the uppersurface 167 of the base 165. In some embodiments, the legs 161 may bespaced apart from each other at regular intervals. For example, thevalve member 110 may have two or more legs 161 equally spaced apart fromeach other. In other embodiments, the legs 161 may be spaced apart fromeach other at irregular intervals. As depicted, adjacent pairs of thelegs 161 each define a flow portion or slot 164 through which fluidentering the cavity 135 from the primary inlet 125 flows into thechamber 150. As illustrated, each of the legs 161 may terminate in aflange 166 at a proximal end of the valve member 110.

In some embodiments, the legs 161 may have a polygonal shape, forexample a rectangular, square or any other suitable polygonal shapeterminating in the flange 166. In other embodiments, the legs 161 mayhave a curved shape, for example a circular, an oval or oblong shapeterminating in the flange 166. However, the various embodiments of thepresent disclosure are not limited the aforementioned configurations,and the shape and spacing of the legs 161 from each other may be variedas desired.

In other embodiments, the main body 160 may be structured with a centralaperture 162 and a plurality of axially extending slots 164 throughwhich fluid flowing into the primary inlet 125 and into the cavity 135may enter the chamber 150.

In operation, when subject to a net upstream force (i.e., a forceapplied by a fluid flowing from the primary inlet 125 towards thechamber 150 that exceeds that of any buoyant force applied by fluid inthe chamber 150), the valve member 110 may be translated distally(downstream) to a position where flange 166 is seated on thecircumferential lip as illustrated in FIG. 2B. Accordingly, the valvemember 110 may be placed in an open state whereby fluid from the primaryIV line 5 may enter the chamber 150 via the primary inlet 125.

FIG. 4 illustrates a perspective view of a valve member 110 and sealingmember 170 of a flow control device 100, in accordance with someembodiments of the present disclosure. As depicted, the valve member 110may include a sealing member 170 coupled to at least a portion of anupper surface 167 of the base 165. The sealing member 170 may beconfigured to contact and seal against an internal surface 122 of theupper housing 120.

In operation, when subject to a net downstream force (i.e., a buoyantforce applied by a fluid in the chamber 150 that exceeds any upstreamforce applied by a fluid flowing from the primary inlet 125 towards thechamber 150), the valve member 110 may be translated proximally(upstream) to a position where sealing member 170 contacts and sealsagainst the internal surface 122 of the upper housing 120, asillustrated in FIG. 2A. Accordingly, fluid flow from the chamber 150into the primary inlet 125 is blocked, thereby preventing fluid backflowinto the primary inlet 125. Similarly, under-infusion of the secondarydrug which commonly occurs as a result of the secondary drug flowingback into the primary inlet 125 from the chamber 150 may be prevented.Preventing backflow of the fluid is advantageous in that it restrictsundesirable particulate matter, for example, contained in a drugdispensed from the secondary IV line 7 from flowing back through thevalve member 100, thereby preventing the patient 50 from receiving theproper drug dosage concentration or from timely delivery of the drug.

FIG. 5 is a cross-sectional view of a flow control device in an openstate when subjected to an upstream force, where the drug level in thechamber is below a predetermined level and the valve member permitsfluid flow from the primary inlet into the chamber, in accordance withsome embodiments of the present disclosure. As depicted, duringoperation, fluid may enter the flow control device 100 via the primaryinlet 125, and flow through the cavity 135 and into the chamber 150 viathe flow portions or slots 164 between adjacent pairs of the legs 161.Where the fluid level in the chamber 150 is below a predetermined level,the upstream force (i.e., force applied by fluid flowing from theprimary IV line 5 into the primary inlet 125) applied to the valvemember 110 causes the valve member 110 to be displaced or otherwise movedistally and be seated on the circumferential lip 175. Thus, the primaryinlet 125 is placed in an open state where the primary inlet 125, thecavity 135, and the chamber 150 are fluidly communicated. In the openstate, fluid from the primary IV line may flow into the chamber 150 viathe cavity 135 and the flow portions or slots 164 between adjacent pairsof the legs 161. As the fluid from the primary IV line continues toenter the chamber 150, the fluid level 152 rises until such a point thatthe fluid in the chamber contacts the lower surface 169 of the base 165of valve member 110. Once the fluid level 152 rises above apredetermined level, the fluid in the chamber exerts a buoyant force onthe base 165, which is greater in magnitude than the upstream forceapplied by the fluid flowing from the primary IV line 5 into the primaryinlet 125. Accordingly, the valve member 110 is then translatedproximally to a position where the sealing member 170 contacts and sealsagainst the internal surface 122 of the upper housing 120, therebyplacing the primary inlet 125 in the closed state, as illustrated inFIG. 6.

FIG. 6 is a cross-sectional view of the flow control device of FIG. 5 ina closed state, where the drug level is above a predetermined amount andapplies a buoyant force to the valve member to block fluid flow from theprimary inlet into the chamber and prevent backflow into the primaryinlet, in accordance with some embodiments of the present disclosure. Asdepicted, during operation, when the buoyant force that exceeds theforce of the fluid flowing in the primary IV line 5 is applied to thebase 165 of valve member 110, the sealing member 170 contacts and sealsagainst the internal surface 122 of the upper housing 120. The primaryinlet 125 is thereby placed in the closed state, and dispensing of thedrug or other fluid from the primary inlet 125 into the chamber ceases.At this time the secondary drug or other fluid in the secondary IV line7 may be dispensed into the chamber 150 via the secondary inlet 130.

Advantageously, since flow from the primary inlet 125 into the chamber150 is blocked at this time, the secondary drug may be dispensed andflow into the chamber 150 without the possibility of flowing backwardsinto the primary inlet 125 and potentially diluting the drug in theprimary IV line 5. Accordingly, under-infusion of the secondary drug orfluid caused by the secondary drug or fluid flowing backwards into theprimary IV line 5 may be prevented.

Preventing backflow of the fluid is further advantageous in that itrestricts undesirable particulate matter, for example, contained in thedrug or fluid dispensed from the secondary IV line 7 from flowing backthrough the valve member 110, thereby preventing the patient fromreceiving the proper drug dosage concentration or from timely deliveryof the drug(s) to the patient 50.

FIG. 7 is a cross-sectional view of the flow control device of FIG. 5 ina closed state, where fluid flows from the secondary inlet into thechamber in accordance with some embodiments of the present disclosure.As depicted, during operation, the secondary drug may be dispensed intothe chamber 150 via the secondary inlet 130 until such time that thesecondary drug dispensing is complete. During this time, fluid in thechamber 150 may also be dispensed to the patient 50 via the outlet 145.As fluid continues to be dispensed to the patient 50 via the outlet 145,the fluid level 152 in the chamber 150 continues to decrease until thefluid level is below the predetermined level as illustrated in FIG. 8.

FIG. 8 is a cross-sectional view of the flow control device of FIG. 5 inan open state, where fluid flow from the secondary inlet into thechamber is complete, and the drug level in the chamber has fallen belowa predetermined level and the valve member is displaced by fluid forceto resume flow from the primary inlet into the chamber, in accordancewith some embodiments of the present disclosure. As the drug in thechamber 150 continues to be dispensed to the patient via the outlet 145,the level of fluid in the chamber 150 falls below the predeterminedlevel and the magnitude of the buoyant force diminishes. As a result,the valve member 110 is displaced distally (towards the chamber 150) andthe fluid flow from the primary IV line into the chamber 150 via theprimary inlet 125 resumes. As depicted, the upstream force applied tothe valve member 110 causes the valve member 110 to seat on thecircumferential lip 175. Accordingly, the primary inlet 125 is placed inan open state where the primary inlet 125, the cavity 135, and thechamber 150 are fluidly communicated. In the open state, fluid from theprimary IV line 5 may flow into the chamber 150 via the cavity 135 andthe flow portions or slots 164 between adjacent pairs of the legs 161.

Table 1, illustrated below provides exemplary calculations for buoyantforce and upstream force applied to the valve member 110 based onexemplary dimensions of the valve member 110. Although the specificdimensions of the valve member 110 are used in the calculations below,the various embodiments of the present disclosure are not limited tothese specific dimensions. The dimensions of the valve member 110 may bevaried based on the desired purpose, and the buoyant force and upstreamforce applied may also vary proportionally based on the dimensions ofthe valve member 110. According to various embodiments of the presentdisclosure, the buoyant force is calculated using the followingequation:

F _(B)=ρ_(f) V _(f) g,

-   -   where F_(B) is the buoyant force, ρ_(f) is the density of the        displaced fluid, V_(f) is the volume of the displaced fluid, and        g is the acceleration due to gravity, 9.8 m/s².

TABLE 1 Parameter Value Unit Volume of valve member base 226.58 mm³0.000 m³ Buoyant force F_(B) = ρ_(f) V_(f) g g 9.81 N/Kg Density of drug997.00 kg/m3 Buoyant force 2.22 N Weight of the body 0.25 gm 0.0025 NDownward force due to primary line 1.96 N Total downward force on theplate 1.96 N Buoyant force 2.21612 N

Accordingly, the various embodiments of the present disclosure areadvantageous in providing a flow control device capable of preventingunder-infusion of the secondary drug by blocking the secondary drug fromflowing backwards into the primary IV line, as discussed previously. Theflow control device of the various embodiments described herein isfurther advantageous as it minimizes the number of separate componentsof an IV set by replacing a check valve and a y-connector with thesingle flow control device. As a result, cost of the IV set may bereduced. Additionally, the various embodiments of the present disclosureare advantageous in reducing workflow steps for the clinician/nursessince no manual operation is necessary for flow regulation as the flowpressure of the secondary drug or fluid is used to regulate flow of theprimary drug or fluid.

Advantageously, since flow from the primary inlet 125 into the chamber150 is blocked at this time, the secondary drug may be dispensed andflow into the chamber 150 without the possibility of flowing backwardsinto the primary inlet 125 and potentially diluting the drug in theprimary IV line 5. Accordingly, under-infusion of the secondary drug orfluid caused by the secondary drug or fluid flowing backwards into theprimary IV line 5 is prevented.

Preventing backflow of the fluid is further advantageous in that itrestricts undesirable particulate matter, for example, contained in thedrug or fluid dispensed from the secondary IV line 7 from flowing backthrough the valve member 110, thereby preventing the patient fromreceiving the proper drug dosage concentration or from timely deliveryof the drug(s) to the patient 50.

FIG. 9 illustrates a cross-sectional view of a flow control device 200having a valve member 110, in accordance with some embodiments of thepresent disclosure. Referring to FIG. 9, similar to the embodiments ofFIG. 2A, a flow control device 200 may include an upper housing 220, alower housing 240 coupled to the upper housing 220, a chamber 250defined between the upper housing 220 and the lower housing 240, and thefloating valve member 110 disposed at least partially in the chamber250. As depicted, the upper housing 220 may include a primary inlet 225for fluidly communicating the primary IV line 5 with the chamber 250,and a secondary inlet 230 for fluidly communicating the secondary IVline 7 with the chamber 250. As depicted, the flow control device 100may be in the form of an axially extending body defining a centrallongitudinal axis Y. The body may be generally cylindrical (or tubular)or may have other shapes with a hollow interior capable of defining achamber.

Similar to the embodiments of FIG. 2A, the primary inlet 225 may have aninternal surface 227, which defines a cavity 235 in which at least aportion of the valve member 110 is disposed. The cavity 235 may form apart of the primary inlet 225, or may be otherwise fluidly communicatedwith the primary inlet 225. Therefore, fluid flowing from the primaryinlet 225 to the channel 250 may flow via the cavity 225. In someembodiments, the internal surface 227 defining the cavity may have acircumferential lip 275 at a distal end thereof. As depicted, thecircumferential lip 275 may be oriented projecting radially inwardstowards a central longitudinal axis Yi of the primary inlet 225.

In accordance with various embodiments of the present disclosure, thelower housing 240 may be coupled distally to the upper housing 220, andmay further define an outlet 245 through which medication or drugs fromthe primary and secondary inlets 225 and 230 may be delivered to thepatient 50. Similar to the embodiments of FIG. 2A, a radial extent ofthe lower housing 240 at a proximal end thereof (the end directlycoupled to the upper housing 220) may be greater than the radial extentat a distal end thereof. However, the various embodiments of the presentdisclosure are not specifically limited to the aforementionedconfiguration and a shape and configuration of the lower housing mayvary for the intended purposes while still embodying the workingprinciples described herein. The lower housing 240 and the upper housing220 may axially contact each other to co-operatively form the chamber250 of the flow control device 200. In the depicted embodiments, thefloating valve member 110 may be mounted partially in the cavity 235 andpartially in the chamber 250 to selectively permit fluid flow from theprimary IV line 5, through the primary inlet 220, and into the chamber250 when a fluid level in the chamber 250 falls below a predeterminedlevel. Furthermore, the valve member 110 may operate to prevent fluidbackflow from the secondary inlet 230 and the chamber 250 when the fluidlevel in the chamber 250 is above the predetermined level and exerts abuoyant force on the valve member 110.

In accordance with various embodiments of the present disclosure, and incontrast to the control flow device 100, the secondary inlet 230 of thecontrol flow device 200 may be positioned at a lower axial position(distally) than the primary inlet 225 with the valve member 110 mountedtherein. For example, secondary inlet 230 may be positioned apredetermined height H below the primary inlet 225 with mounted valvemember 110. The aforementioned configuration ensures that the valvemember 110 remains above the level of the secondary line to allow thevalve member 210 to function as intended.

FIG. 10 illustrates a cross-sectional view of a flow control device 300having a valve member 310, in accordance with some embodiments of thepresent disclosure. Referring to FIG. 10, similar to the embodiments ofFIG. 2A, the flow control device 300 may include an upper housing 120, alower housing 140 coupled to the upper housing 120, and a chamber 150defined between the upper housing 120 and the lower housing 140. Asdepicted, the upper housing 120 may include a primary inlet 125 forfluidly communicating the primary IV line 5 with the chamber 150, and asecondary inlet 130 for fluidly communicating the secondary IV line 7with the chamber 150. Since the upper and lower housings 120 and 140,and the chamber 150 as well as their connection and fluid communicationwith respect to each other are identical as described above with respectto flow control device 100 of FIG. 2A, a further detailed descriptionthereof shall be omitted with respect to the flow control device 300.According to various embodiments, the control device 300 may furtherinclude a valve member 310 disposed at least partially in the chamber150.

FIG. 11 illustrates a perspective view of the valve member of FIG. 10,in accordance with some embodiments of the present disclosure. Asdepicted, the valve member 310 may include a base 365 and a main body360 extending proximally from the base 365. In some embodiments, thebase 365 may be in the form of a disc or any other circular orsemi-circular plate having an upper surface 367 and a lower surface 369.The size or surface area of the base 365 may be selected specifically toallow for maximum exposure to the fluid in the chamber 150 so as toovercome fluid force of the fluid entering the primary inlet 125 fromthe primary IV tubing 5. For example, the greater the size of the base365, the greater the surface area acted upon by the fluid in the chamber150. Accordingly, the valve member 310 may be designed so as open andclose the primary inlet 125 based on a specific threshold force. Inparticular, the base 365 differs in structure to the base 165 of thevarious embodiment described in FIGS. 3 and 4 in that the base 365 mayhave a greater surface area than that of the base 165. For example, asillustrated, the base 365 may be in the shape of a semi-circular platehaving a greater radius than the radius of the circular plate-shapedbase 165. The aforementioned configuration of the base 365 may befurther advantageous over that of the base 165 in that a greater fluidforce from the primary IV line 5 will be required to displace the valvemember 310 and open the primary inlet 125 when the level of fluid in thechamber 150 is above the predetermined level. This is the case becausethe greater surface area of the base 365 is subject to a larger buoyantforce from the fluid in the chamber (see Table 2 below). Accordingly,the valve member 365 is less likely to leak or otherwise open whenunintended as a result of excessive fluid pressure in the primary IVline 5.

Similar to the embodiments described above with respect to the valvemember 110, the main body 360 of the valve member 310 may have aplurality of legs 361 extending longitudinally from the base 365 intothe cavity 135 of the primary inlet 125. The legs 361 may each extendlongitudinally from an upper surface 367 of the base 365. In someembodiments, the legs 361 may be oriented substantially perpendicularlywith respect to the upper surface 367 of the base 365. In particular,the legs 361 may extend and protrude substantially perpendicularly at apredetermined height above the upper surface 367 of the base 365. Insome embodiments, the legs 361 may be spaced apart from each other atregular intervals. For example, the valve member 310 may have two ormore legs 361 equally spaced apart from each other. In otherembodiments, the legs 361 may be spaced apart from each other atirregular intervals. As depicted, adjacent pairs of the legs 361 eachdefine a flow portion or slot 364 through which fluid entering thecavity 135 from the primary inlet 125 flows into the chamber 150. Asillustrated, each of the legs 361 may terminate in a flange 366 at aproximal end of the valve member 310.

In some embodiments, the legs 361 may have a polygonal shape, forexample a rectangular, square or any other suitable polygonal shapeterminating in the flange 366. In other embodiments, the legs 361 mayhave a curved shape, for example a circular, an oval or oblong shapeterminating in the flange 366. However, the various embodiments of thepresent disclosure are not limited the aforementioned configurations,and the shape and spacing of the legs 361 from each other may be variedas desired.

In other embodiments, the main body 360 may be structured with a centralaperture 362 and a plurality of axially extending slots 364 throughwhich fluid flowing into the primary inlet 125 and into the cavity 135may enter the chamber 150.

Since the operation and function of the flow control device 300 andvalve member 310 is similar to that of the flow control device 100 andvalve member 110, and a detailed description of how the flow controldevice 100 and valve member 110 function was provided above with respectto FIGS. 2A and 5-8, a detailed description thereof shall be omittedwith respect to the flow control device 300 and valve member 310.

Table 2, illustrated below provides exemplary calculations for buoyantforce and upstream force applied to the valve member 310 based onexemplary dimensions of the valve member 310. Although the specificdimensions of the valve member 310 are used in the calculations below,the various embodiments of the present disclosure are not limited tothese specific dimensions. The dimensions of the valve member 310 may bevaried based on the desired purpose, and the buoyant force and upstreamforce applied may also vary proportionally based on the dimensions ofthe valve member 310. According to various embodiments of the presentdisclosure, the buoyant force is calculated using the followingequation:

F _(B)=ρ_(f) V _(f) g,

-   -   where F_(B) is the buoyant force, ρ_(f) is the density of the        displaced fluid, V_(f) is the volume of the displaced fluid, and        g is the acceleration due to gravity, 9.8 m/s′.

TABLE 2 Parameter Value Unit Volume of valve member base 243 mm³ 0.000m³ Buoyant force F_(B) = ρ_(f) V_(f) g g 9.81 N/Kg Density of drug997.00 kg/m3 Buoyant force 2.37667851 N Weight of the body 0.22 gm0.002156 N Downward force due to primary line 1.96 N Total downwardforce on the plate 1.962156 N Buoyant force 2.37667851 N

FIG. 12 illustrates a cross-sectional view of a flow control device 400having a valve member 410, in accordance with some embodiments of thepresent disclosure. Referring to FIG. 12, similar to the embodiments ofFIG. 2A, the flow control device 400 may include an upper housing 120, alower housing 140 coupled to the upper housing 120, and a chamber 150defined between the upper housing 120 and the lower housing 140. Asdepicted, the upper housing 120 may include a primary inlet 125 forfluidly communicating the primary IV line 5 with the chamber 150, and asecondary inlet 130 for fluidly communicating the secondary IV line 7with the chamber 150. Since the upper and lower housings 120 and 140,and the chamber 150 as well as their connection and fluid communicationwith respect to each other are identical as described above with respectto flow control device 100 of FIG. 2A, a further detailed descriptionthereof shall be omitted with respect to the flow control device 400.According to various embodiments, the control device 400 may furtherinclude a valve member 410 disposed at least partially in the chamber150.

FIG. 13 illustrates a perspective view of the valve member 410 of FIG.12, in accordance with some embodiments of the present disclosure. Asdepicted, the valve member 410 may include a base 465 and a main body460 extending proximally from the base 465. In some embodiments, thebase 465 may be in the form of a disc or any other circular orsemi-circular plate having an upper surface 467 and a lower surface 469.The size or surface area of the base 465 may be selected specifically toallow for maximum exposure to the fluid in the chamber 150 so as toovercome fluid force of the fluid entering the primary inlet 125 fromthe primary IV tubing 5. For example, the greater the size of the base465, the greater the surface area acted upon by the fluid in the chamber150. Accordingly, the valve member 410 may be designed so as open andclose the primary inlet 125 based on a specific threshold force. Inparticular, the base 465 differs in structure to the base 165 of thevarious embodiment described in FIGS. 3 and 4 in that the base 465 mayhave a greater surface area than that of the base 165. For example, asillustrated, the base 465 may be in the shape of a circular plate havinga greater diameter than the diameter of the circular plate-shaped base165 and spanning an area below both the primary and secondary inlets 125and 130. As depicted, the base 465 may have an aperture 464 positionedat a location corresponding to an opening at a distal end of thesecondary inlet 130 to prevent the base 465 from occluding fluid flowfrom the secondary inlet 7 into the chamber 150. The aforementionedconfiguration of the base 465 may be further advantageous over that ofthe base 165 in that a greater fluid force from the primary IV line 5will be required to displace the valve member 410 (without obstructingflow through the secondary inlet 130) and open the primary inlet 125when the level of fluid in the chamber 150 is above the predeterminedlevel. This is the case because the greater surface area of the base 465is subject to a larger buoyant force from the fluid in the chamber 150(see Table 3 below). Accordingly, the valve member 465 is less likely toleak or otherwise open when not intended to as a result of excessivefluid pressure in the primary IV line 5.

Similar to the embodiments described above with respect to the valvemember 110, the main body 460 of the valve member 410 may have aplurality of legs 461 extending longitudinally from the base 465 intothe cavity 135 of the primary inlet 125. The legs 461 may each extendlongitudinally from an upper surface 467 of the base 465. In someembodiments, the legs 461 may be oriented substantially perpendicularlywith respect to the upper surface 467 of the base 465. In particular,the legs 461 may extend and protrude substantially perpendicularly at apredetermined height above the upper surface 467 of the base 465. Insome embodiments, the legs 461 may be spaced apart from each other atregular intervals. For example, the valve member 410 may have two ormore legs 461 equally spaced apart from each other. In otherembodiments, the legs 461 may be spaced apart from each other atirregular intervals. As depicted, adjacent pairs of the legs 461 eachdefine a flow portion or slot 464 through which fluid entering thecavity 135 from the primary inlet 125 flows into the chamber 150. Asillustrated, each of the legs 461 may terminate in a flange 466 at aproximal end of the valve member 410.

In some embodiments, the legs 461 may have a polygonal shape, forexample a rectangular, square or any other suitable polygonal shapeterminating in the flange 466. In other embodiments, the legs 461 mayhave a curved shape, for example a circular, an oval or oblong shapeterminating in the flange 466. However, the various embodiments of thepresent disclosure are not limited the aforementioned configurations,and the shape and spacing of the legs 461 from each other may be variedas desired.

In other embodiments, the main body 460 may be structured with a centralaperture 462 and a plurality of axially extending slots 464 throughwhich fluid flowing into the primary inlet 125 and into the cavity 135may enter the chamber 150.

Since the operation and function of the flow control device 400 andvalve member 410 is similar to that of the flow control device 100 andvalve member 110, and a detailed description of how the flow controldevice 100 and valve member 110 function was provided above with respectto FIGS. 2A and 5-8, a detailed description thereof shall be omittedwith respect to the flow control device 400 and valve member 410.

Table 3, illustrated below provides exemplary calculations for buoyantforce and upstream force applied to the valve member 410 based onexemplary dimensions of the valve member 410. Although the specificdimensions of the valve member 410 are used in the calculations below,the various embodiments of the present disclosure are not limited tothese specific dimensions. The dimensions of the valve member 410 may bevaried based on the desired purpose, and the buoyant force and upstreamforce applied may also vary proportionally based on the dimensions ofthe valve member 410. According to various embodiments of the presentdisclosure, the buoyant force is calculated using the followingequation:

F _(B)=ρ_(f) V _(f) g,

where F_(B) is the buoyant force, ρ_(f) is the density of the displacedfluid, V_(f) is the volume of the displaced fluid, and g is theacceleration due to gravity, 9.8 m/s′.

TABLE 3 Parameter Value Unit Volume of valve member base 245 mm³ 0.000m³ Buoyant force F_(B) = ρ_(f) V_(f) g g 9.81 N/Kg Density of drug997.00 kg/m3 Buoyant force 2.39623965 N Weight of the body 0.22 gm0.002156 N Downward force due to primary line 1.96 N Total downwardforce on the plate 1.962156 N Buoyant force 2.39623965 N

The present disclosure is provided to enable any person skilled in theart to practice the various aspects described herein. The disclosureprovides various examples of the subject technology, and the subjecttechnology is not limited to these examples. Various modifications tothese aspects will be readily apparent to those skilled in the art, andthe generic principles defined herein may be applied to other aspects.

A reference to an element in the singular is not intended to mean “oneand only one” unless specifically so stated, but rather “one or more.”Unless specifically stated otherwise, the term “some” refers to one ormore. Pronouns in the masculine (e.g., his) include the feminine andneuter gender (e.g., her and its) and vice versa. Headings andsubheadings, if any, are used for convenience only and do not limit theinvention.

The word “exemplary” is used herein to mean “serving as an example orillustration.” Any aspect or design described herein as “exemplary” isnot necessarily to be construed as preferred or advantageous over otheraspects or designs. In one aspect, various alternative configurationsand operations described herein may be considered to be at leastequivalent.

As used herein, the phrase “at least one of” preceding a series ofitems, with the term “or” to separate any of the items, modifies thelist as a whole, rather than each item of the list. The phrase “at leastone of” does not require selection of at least one item; rather, thephrase allows a meaning that includes at least one of any one of theitems, and/or at least one of any combination of the items, and/or atleast one of each of the items. By way of example, the phrase “at leastone of A, B, or C” may refer to: only A, only B, or only C; or anycombination of A, B, and C.

A phrase such as an “aspect” does not imply that such aspect isessential to the subject technology or that such aspect applies to allconfigurations of the subject technology. A disclosure relating to anaspect may apply to all configurations, or one or more configurations.An aspect may provide one or more examples. A phrase such as an aspectmay refer to one or more aspects and vice versa. A phrase such as an“embodiment” does not imply that such embodiment is essential to thesubject technology or that such embodiment applies to all configurationsof the subject technology. A disclosure relating to an embodiment mayapply to all embodiments, or one or more embodiments. An embodiment mayprovide one or more examples. A phrase such an embodiment may refer toone or more embodiments and vice versa. A phrase such as a“configuration” does not imply that such configuration is essential tothe subject technology or that such configuration applies to allconfigurations of the subject technology. A disclosure relating to aconfiguration may apply to all configurations, or one or moreconfigurations. A configuration may provide one or more examples. Aphrase such a configuration may refer to one or more configurations andvice versa.

In one aspect, unless otherwise stated, all measurements, values,ratings, positions, magnitudes, sizes, and other specifications that areset forth in this specification, including in the claims that follow,are approximate, not exact. In one aspect, they are intended to have areasonable range that is consistent with the functions to which theyrelate and with what is customary in the art to which they pertain.

It is understood that the specific order or hierarchy of steps, oroperations in the processes or methods disclosed are illustrations ofexemplary approaches. Based upon implementation preferences orscenarios, it is understood that the specific order or hierarchy ofsteps, operations or processes may be rearranged. Some of the steps,operations or processes may be performed simultaneously. In someimplementation preferences or scenarios, certain operations may or maynot be performed. Some or all of the steps, operations, or processes maybe performed automatically, without the intervention of a user. Theaccompanying method claims present elements of the various steps,operations or processes in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

All structural and functional equivalents to the elements of the variousaspects described throughout this disclosure that are known or latercome to be known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe claims. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the claims. No claim element is to be construedunder the provisions of 35 U.S.C. § 112 (f) unless the element isexpressly recited using the phrase “means for” or, in the case of amethod claim, the element is recited using the phrase “step for.”Furthermore, to the extent that the term “include,” “have,” or the likeis used, such term is intended to be inclusive in a manner similar tothe term “comprise” as “comprise” is interpreted when employed as atransitional word in a claim.

The Title, Background, Summary, Brief Description of the Drawings andAbstract of the disclosure are hereby incorporated into the disclosureand are provided as illustrative examples of the disclosure, not asrestrictive descriptions. It is submitted with the understanding thatthey will not be used to limit the scope or meaning of the claims. Inaddition, in the Detailed Description, it can be seen that thedescription provides illustrative examples and the various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed subject matter requires morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed configuration or operation. The followingclaims are hereby incorporated into the Detailed Description, with eachclaim standing on its own as a separately claimed subject matter.

The claims are not intended to be limited to the aspects describedherein, but are to be accorded the full scope consistent with thelanguage of the claims and to encompass all legal equivalents.Notwithstanding, none of the claims are intended to embrace subjectmatter that fails to satisfy the requirement of 35 U.S.C. § 101, 102, or103, nor should they be interpreted in such a way.

What is claimed is:
 1. A flow control device, comprising: an upperhousing including: a primary inlet having an internal surface defining acavity; and a secondary inlet; a lower housing defining an outlet of theflow control device; a chamber interposed between and defined by theupper and lower housings for fluidly connecting the primary andsecondary inlets with the outlet; and a valve member reciprocallydisposed at least partially in the cavity and partially in the chamberto (i) selectively permit fluid flow in the primary inlet in a firstdirection when a fluid level in the chamber is below a predeterminedlevel, and (ii) prevent fluid backflow in a second direction opposite tothe first direction when the fluid level in the chamber is above thepredetermined level.
 2. The flow control device of claim 1, wherein thevalve member comprises a base and a main body extending proximally fromthe base, the main body comprising a flange at a proximal end thereof.3. The flow control device of claim 2, wherein the main body furthercomprises a central aperture and a plurality of axially extending slotsthrough which fluid flowing into the primary inlet and the cavity entersthe chamber.
 4. The flow control device of claim 2, wherein: theinternal surface defining the cavity comprises a circumferential lip ata distal end thereof, the circumferential lip projecting radiallyinwards towards a central longitudinal axis of the primary inlet; andthe main body flange is configured to be seated on the circumferentiallip when the valve member is subjected to a net axial force in the firstdirection.
 5. The flow control device of claim 2, wherein the main bodyfurther comprises a plurality of legs extending longitudinally from thebase into the cavity of the primary inlet.
 6. The flow control device ofclaim 5, wherein the plurality of legs are radially spaced apart about acentral longitudinal axis of the main body, and each spacing betweenadjacent legs defines a flow portion through which fluid entering theprimary inlet and into the cavity enters the chamber.
 7. The flowcontrol device of claim 5, wherein: each of the legs comprises a portionof the main body flange and the internal surface defining the cavitycomprises a circumferential lip at a distal end thereof, thecircumferential lip projecting radially inwards towards a centrallongitudinal axis of the primary inlet; and each main body flangeportion is configured to be seated on the circumferential lip when thevalve member is subjected to a net axial force in the first direction.8. The flow control device of claim 2, wherein the base comprises asubstantially circular plate sharing a common central axis with theprimary inlet.
 9. The flow control device of claim 2, wherein the basecomprises a semi-circular plate.
 10. The flow control device of claim 2,wherein the base comprises: a substantially circular plate spanning anarea below both the primary and secondary inlets: and an aperturepositioned at a location corresponding to an opening at a distal end ofthe secondary inlet to prevent the base from occluding fluid flow fromthe secondary inlet into the chamber.
 11. The flow control device ofclaim 2, further comprising a sealing member coupled to at least aportion of the base, the sealing member configured to contact aninternal surface of the upper housing when the fluid level in thechamber is above the predetermined level.
 12. The flow control device ofclaim 1, wherein the secondary inlet is disposed at a lower axialposition than the primary inlet and valve member mounted therein. 13.The flow control device of claim 1, further comprising an air ventpositioned on the upper housing for removing air during priming.
 14. Anintravenous (IV) set, comprising: a primary IV line and a secondary IVline; and a flow control device comprising: an upper housing, a lowerhousing coupled to the upper housing, and a chamber defined between theupper and lower housings, the upper housing comprising a primary inletfluidly communicating the primary IV line with the chamber, and asecondary inlet fluidly communicating the secondary IV line with thechamber; and a valve member having a base disposed in the chamber and aplurality of legs extending longitudinally from the base into theprimary inlet, the floating valve member being displaceable in aproximal direction by a buoyant force exerted on the base when a levelof fluid in the chamber exceeds a predetermined level.
 15. The IV set ofclaim 14, wherein: the valve member blocks fluid flow through theprimary inlet when the buoyant force exceeds force of fluid entering theprimary inlet from the primary IV line; and the valve member permitsfluid flow through the primary inlet when a fluid level in the chamberis below predetermined level.
 16. The IV set of claim 14, wherein theplurality of legs are radially spaced apart about a central longitudinalaxis of the main body, and each spacing between adjacent legs defines aflow portion through which fluid entering the primary inlet flows intothe chamber.
 17. The IV set of claim 16, wherein: each of the legscomprises a portion of the main body flange; the primary inlet comprisesan internal surface having a circumferential lip at a distal endthereof, the circumferential lip projecting radially inwards towards acentral longitudinal axis of the primary inlet; and each main bodyflange portion is configured to be seated on the circumferential lipwhen the valve member is subjected to a net upstream force.
 18. The IVset of claim 14, further comprising a sealing member coupled to an uppersurface of the base, the sealing member configured to contact aninternal surface of the upper housing when subjected to the buoyantforce from fluid in the chamber.
 19. The IV set of claim 14, wherein thebase comprises: a substantially circular plate sharing a common centralaxis with the upper housing: and an aperture positioned at a locationcorresponding to an opening at a distal end of the secondary inlet toallow fluid flow from the secondary inlet into the chamber.
 20. The IVset of claim 14, wherein the secondary inlet is disposed at a loweraxial position than the primary inlet and valve member mounted therein.